Optically active pyrrolidine derivative

ABSTRACT

Optically active pyrrolidine derivative represented by the following formula (XI): ##STR1## wherein R 1  represents a benzyl group R 2  represents an alkyl group having 1 to 6 carbon atoms, R 3  represents an alkyl group having 1 to 6 carbon atoms, a benzyl group or an allyl group, R 4  is selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may be substituted with a protected hydroxyl group, a vinyl group, a phenyl group which may be substituted, a benzyl group which may be substituted, and a heterocyclic ring having 1 to 4 nitrogen or/and oxygen atoms, and R 5  represents a hydrogen atom or a methyl group. 
     This compound can be an intermediate for synthesis of carbapenem antibiotic compounds.

DESCRIPTION Technical Field

This invention is to provide novel carbapenam derivatives which areuseful as preparation intermediates for synthesis of carbapenems whichare now developing into various medicines such as β-lactam antibioticshaving excellent antibacterial activities, a process for preparing thesame, and also novel optically active pyrrolidine derivatives and aprocess for preparing the same.

Background Art

As for the novel carbapenam derivatives according to the presentinvention, various derivatives have been synthesized in order tostrengthen antibacterial activities of carbapenem antibiotics orheightening the stability against an enzyme DHP-1 which deactivatescarbapenems.

It is one of the means of synthesizing derivatives to introduce ahydroxyl group to the 6-position, but almost all the synthetic methodsof carbapenems which have heretofore been developed relate to synthesisof 6-hydroxyethylcarbapenems. According to these methods, however, it isdifficult to synthesize 6-hydroxy-6-hydroxyethylcarbapenems.

Among preparation methods of 6-hydroxycarbapenems which have heretoforebeen developed, there is a method where the 6-position of6-ethylcarbapenems is hydroxylated (Bull. Chem. Soc. Jpn., 60, 2091(1987)), but there is no method where a hydroxyl group is introduced tothe 6-position of 6-hydroxyethyl-substituted carbapenems. Also, as asynthetic method of a 3-hydroxy-3-hydroxyethylazethidinone derivativewhich can be considered to be an intermediate for synthesis of suchcarbapenems, there has been known a method by T. Durst (TetrahdedronLetters, 31, 3249 (1990)). However, this method involves many steps andalso requires many further steps for converting it into a finalcarbapenem.

Under such a technical background, one of the objects of the presentinvention is to provide intermediates for synthesis of6-hydroxy-6-hydroxyethylcarbapenems and a process for preparing thesame.

Also, as for the novel optically active pyrrolidine derivativesaccording to the present invention, it is difficult to producecarbapenems by fermentation using bacteria due to their potentantibacterial activities so that it has been desired to develop asynthetic preparation process. As synthetic methods, there have beengenerally employed those ones where the optically active β-lactamportion is first synthesized and then the 5-membered ring is formed (T.Kametani et al., Heterocycles, 17, 463 (1982) and 25, 729 (1987)). As amore general method for synthesizing various kinds of substitutedcarbapenems as compared to these methods, the present inventors havedeveloped a method in which L-pyrroglutamic acid derivatives are used asa starting material (S. Nozoe et al., Tetrahedron Letters, 29, 4305(1988); Japanese Patent Application Laid-Open No. 72667/1988).

The main part of the above method using L-pyrroglutamic acid derivativesas a starting material can be shown by the following figure. ##STR2##

When X⁴ is an alkyl group, a desired product can be obtained in a highyield by the said method, but when X⁴ is a hydroxyalkyl grouprepresented by the formula: ##STR3## is to be synthesized, a reactionyield of the compound 2 was not satisfactory for practical purposes.

In such a technical background, another object of the present inventionis to develop a process for synthesizing, from an inexpensiveL-pyrroglutamic acid derivative, 6-hydroxyalkylcarbapenems which areconsidered to be essential for developing potent antibacterialactivities and a wide antibacterial spectrum, and for accomplishing theabove, it is necessary to develop a process for synthesizing thecompounds 3 and/or 4 in the above figure effectively.

DISCLOSURE OF THE INVENTION

First, the novel carbapenam derivatives of the present invention and aprocess for preparing the same is to be explained.

The present inventors have intensively studied in view of the aboveproblems and, as a result, found that novel carbapenams represented bythe following general formula (I) which are diols and can be usefulintermediates for synthesis of 6-hydroxy-6-hydroxyethylcarbapenem can beeasily produced by reacting a 6-ethylidenecarbapenam which can be easilyobtained and represented by the following general formula (II) withosmium tetroxide, and accomplished the present invention based on thesefindings. ##STR4## wherein R¹ represents a hydrogen atom or an organicgroup which can be eliminated under acidic or alkaline conditions, orreductively such as a methoxycarbonyl group or a benzyloxycarbonylgroup, R² represents a hydrogen atom or a carboxyl-protective group suchas a methyl group, and steric configuration at the 5-position representsthe (R) configuration. ##STR5## wherein R¹, R² and steric configurationat the 5-position are respectively the same as those of the formula(II).

Substrate ethylidenecarbapenams represented by the formula (II) can beeasily prepared, for example, when R¹ represents a methoxycarbonyl groupand R² represents a methyl group, by the oxidative elimination of the6-phenylselenoether of the corresponding carbapenam. ##STR6##

Also, when R¹ represents a hydrogen atom and R² represents acarboxyl-protective group, they can be produced by subjecting acorresponding 6-hydroxyethylcarbapenam to methanesulfonylation, followedby the action of a base such as DBU(1,8-diazabicyclo[5,4,0]-7-undecene). ##STR7##

The reaction scheme in which a carbapenam derivative of the presentinvention represented by the general formula (I) is synthesized from a6-ethylidenecarbapenam represented by the general formula (II) is shownbelow. ##STR8##

In the present reaction, the introduction of the two hydroxyl groups canbe carried out by the action of osmium tetroxide on the6-ethylidenecarbapenam (II). Also, it can be carried out by the actionof osmium tetroxide together with a tertiary amine-N-oxide, suitablyN-methylmorpholine-N-oxide. Osmium tetroxide may be used in an amount of0.05 to 1 equivalent or so. In this reaction, when a cis (Z)ethylidenecarbapenam is used, the 6 (S) and 8 (S) isomer can beselectively obtained and, when a trans (E)-ethylidenecarbapenam is used,the 6(S) and 8 (R) isomer can be selectively obtained.

The present reaction can be carried out at 0° C. or so and at roomtemperature, and it is preferably carried out at 0° C. or so from theview points of stereoselectivity, etc.

As the reaction solvent, a solvent such as diethyl ether, benzene,pyridine, water, acetone, or a mixture of two or more thereof is used,and a 1:1 to 2 mixture of water and acetone is preferably used from theview points of solubility of the reactants, etc.

As for the reaction time, the reaction usually requires several hours toone day or so.

As for separation of a desired product from a reaction mixture, it canbe easily carried out by a usual extraction operation followed by ausual purification operation such as chromatography using silica gel.

As for the process for producing the carbapenem skeleton from a novelcarbapenam derivative represented by the general formula (I), forexample, when R¹ represents a hydrogen atom and R² represents acarboxyl-protective group, the skeleton can be easily produced by usingthe method which was already reported by the present inventors(Abstracts of the 29th Symposium on the Chemistry of Natural Products,Japan, p. 87 (1987)). Also, when R¹ represents an alkoxycarbonyl groupand R² represents a carboxyl-protective group, it can be produced by analready known method (Bull. Chem. Soc. Jpn., 60, 2091 (1987)).

Next, novel optically active pyrrolidine derivatives of the presentinvention and a process for producing the same are to be explained.

In order to solve the above problem, the present inventors have made anintensive study on an effective synthetic method of the compounds 3 and4 in which X⁴ is a hydroxyalkyl group or those compounds in which thegroup is suitably protected in the aforementioned figure, and as theresult, they have found that optically active pyrrolidine derivativeswhich are novel compounds represented by the following general formula(XI) can be synthesized by reacting an optically active pyrrolidinederivative which is also a novel compound represented by the followinggeneral formula (XII) with a base and a carbonyl compound represented bythe following general formula (XIII), and have also confirmed that acompound represented by the general formula (XI) can be converted into acarbapenem compound with good efficiency. The present invention has beenmade on these findings. ##STR9##

In the above formulae, R¹ represents a benzyl group, R² represents analkyl group having 1 to 6 carbon atoms, R³ represents an alkyl grouphaving i to 6 carbon atoms, a benzyl group or an allyl group, R⁴represents either of a hydrogen atom, an alkyl group having 1 to 6carbon atoms which may be substituted by a protected-hydroxyl group, avinyl group, a phenyl group which may be substituted, a benzyl groupwhich may be substituted, or a heterocyclic ring containing 1 to 4nitrogen atom(s) or/and oxygen atom(s), and R⁵ represents a hydrogenatom or a methyl group, respectively.

In the reaction from the formula (XII) to the formula (XI), it is one ofthe characteristic features of the present invention that a benzyl groupis used as the N-protective group R¹. When other protective groups, forexample, a benzyloxycarbonyl group, a t-butyloxycarbonyl group, etc.,are used, there are provided various products. Only when a benzyl groupis used, the reaction for producing a compound represented by thegeneral formula (XI) can proceed without being accompanied by any sidereaction and in a satisfactory yield thereof. Further, a benzyl groupcan be easily removed by catalytic hydrogenolysis.

Pyrrolidine derivatives (XII) which are compounds of the presentinvention and are also a starting material of the process of the presentinvention can be synthesized in a high yield by reacting a pyrrolidinederivative (which corresponds to the compound of the formula (XII) inwhich R¹ is a hydrogen atom) obtained from an L-pyrroglutamic acidderivative according to the methods described in Japanese PatentApplication Laid-Open No. 72667/1988 and Tetrahedron Letters, 29, 4305(1988), with benzyl chloride or benzyl bromide at a temperature of 0° to50° C. in an organic solvent such as dichloromethane, chloroform,tetrahydrofuran, etc., in the presence of a base such as triethylamine,potassium carbonate, etc.

An optically active pyrrolidine derivative (XI) can be synthesized bytreating an optically active pyrrolidine derivative (XII) with a basefollowed by reacting a carbonyl compound (XIII).

As the base, there may be used lithium diisopropylamide, lithiumhexamethyldisilazide, potassium hexamethyldisilazide, potassiumt-butoxide, etc.

As the reaction solvent, there may be used an ether solvent such astetrahydrofuran, ethyl ether, etc., a hydrocarbon solvent such astoluene, etc., an aprotic polar solvent such as N,N-dimethylformamide,etc., or a mixture of two or more thereof.

Also, there may be, though not essential, added hexamethylphosphorictriamide, N,N'-dimethylpropylene urea,N,N,N',N'-tetramethylethylenediamine, etc. as a reaction aid. By usingsuch a reaction aid, a merit of stabilizing anions, etc. can beobtained.

The reaction temperature is generally from -80° C. or so to roomtemperature, preferably -20° to -70° C. from the view point ofindustrial utilization.

A carbonyl compound (XIII) is desirably used in at least 1 equivalent toa compound (XII), and it is added to the reaction solution, preferablyas a solution of the above reaction solvent.

After completion of the reaction, purification can be carried out byusual methods, such as extraction, washing, recrystallization andchromatography.

The optically active pyrrolidine derivatives (XI) can be led tocompounds having potent antibacterial activities such as carbapenemshaving a hydroxyalkyl group at the 6-position including, for example,thienamycin, carpetimycin derivatives, etc. by the method as shown inReference examples. Accordingly, the optically active pyrrolidinederivatives of the present invention represented by the general formulae(XI) and (XII) are useful as intermediates for the synthesis ofcarbapenems.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be further explained by the followingExamples.

EXAMPLE 1 ##STR10##

82 mg (0.324 mmol) of the ethylidenecarbapenam (1) was dissolved in amixed solvent of 4 ml of acetone and 2 ml of water. To the solution wereadded 150 mg (1.28 mmol) of N-methylmorpholine N-oxide and 0.4 ml (0.066mmol) of aqueous 0.164M osmium tetroxide solution, and the mixture wasstirred at 0° C. overnight. An aqueous 10% Na₂ SO₃ solution was added tothe reaction mixture and the mixture was stirred at room temperature forfurther one hour. Thereafter, the reaction mixture was saturated withsodium chloride and extracted with dichloromethane. After drying overMgSO₄, the solvent was removed by distillation. The residue was purifiedby a preparative TLC (ethyl acetate) to obtain the diol (2). 53.7 mg(57.7%).

NMR (CDCl₃, ppm): 1.20 (3H, d), 1.65 (2H, br), 1.85-2.10 (2H, m), 2.65(2H, m), 3.82 (6H, s), 3.95 (1H, t), 4.38 (1H, q).

EXAMPLE 2 ##STR11##

In the same manner as in Example 1, 16 mg (21.7%) of the diol (4) wasobtained from 65 mg of the ethylidenecarbapenam (3).

NMR (CDCl₃, ppm): 1.38 (3H, d, J=6.6 Hz), 1.80 (2H, br), 2.20 (2H, m),2.65 (2H, m), 3.80 (3H, s), 3.82 (3H, s), 3.90 (1H, m), 4.20 (1H, br).

EXAMPLE 3 ##STR12##

In the same manner as in Example 1, 8 mg (17%) of the diol (6) wasobtained from 40 mg of the ethylidenecarbapenam (5).

NMR (CDCl₃, ppm): 1.30 (3H, d, J=6.6 Hz), 1.95 (6H, m), 3.59 (1H, J=6.9Hz, 8.4 Hz), 3.73 (3H, s), 3.84 (1H, dd, J=5.1 Hz, 9 Hz), 4.26 (1H, q,J=6.6 Hz).

IR (CHCl₃, cm⁻¹): 1781, 1737, 1216.

EXAMPLE 4 ##STR13##

In the same manner as in Example 1, 8 mg (11.5%) of the diol (8) wasobtained from 59 mg of the ethylidenecarbapenam (7).

NMR (CDCl₃, ppm): 1.31 (3H, d, J=6.6 Hz), 1.6 (2H, br), 1.5-2.1 (4H, m),3.51 (1H, t, J=7.5 Hz), 3.71 (3H, s), 3.79 (1H, t, J=6.9 Hz), 4.13 (1H,q, J=6.6 Hz).

In the following Examples, the following abbreviations are used.

Me: methyl

^(i) Pr: isopropyl

Bn: benzyl

^(t) Bu: t-butyl

Z: benzyloxycarbonyl

THF: tetrahydrofuran

NMR: nuclear magnetic resonance spectrum (proton)

IR: infrared absorption spectrum

Also, the proton NMR spectra (300 MHz) is shown by (ppm) values usingchloroform-d as the solvent and tetramethyl silane as the internalstandard unless otherwise specifically mentioned, and coupling constants(J) are shown by Hz.

EXAMPLE 5 Synthesis of Isopropyl(2S,5R)-1-Benzyl-5-[2-Hydroxy-2-Methyl-1-(t-Butoxycarbonyl)Propyl]Pyrrolidine-2-Carboxylate(Compound 2) ##STR14##

Under an argon atmosphere, n-butyl lithium (1.56 M/hexane, 4.2 ml, 6.6mmol) was added dropwise to a THF (28 ml) solution of diisopropylamine(1.0 ml, 7.1 mmol) at -45° C., and the mixture was stirred underice-cooling for 12 minutes. To the solution was added dropwise a THF (4ml) solution of isopropyl(2S,5R)-1-benzyl-5-(t-butoxycarbonyl)pyrrolidine-2-carboxylate (Compound1, 2.16 g, 5.98 mmol) at -70° C. and the mixture was stirred for 30minutes. Then, a THF (1 ml) solution of acetone (0.60 ml, 8.2 mmol) wasadded dropwise and the mixture was stirred for one hour.

The reaction was stopped by adding 40 ml of aqueous 20% ammoniumchloride solution. The reaction mixture was extracted with ethylacetate, and the ethyl acetate solution was washed with an aqueousNaCl-saturated solution and dried over anhydrous sodium sulfate. Thesolvent was removed by distillation under reduced pressure. The residuewas divided into two portion, and each portion was subjected to a mediumpressure silica gel column chromatography (Lobar size B, ethylacetate-hexane 1:6) to recover the unreacted starting material (Compound1, 711 mg, 33%) as well as to obtain a mixture of the two isomers ofCompound 2 (Compounds 2a and 2b (29:71), colorless viscous liquid, 1.31g, 52%).

Spectrum data of isopropyl(2S,5R)-1-benzyl-5-[(R)-2-hydroxy-2-methyl-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 2a);

IR (neat): 1720 cm⁻¹.

NMR: 1.01 (3H, d, J=6.3), 1.05 (3H, d, J=6.2), 1.26 (3H, s), 1.44 (3H,s), 1.47 (9H, s), 1.6-1.75 (1H, m, 4-CH), 1.90-2.06 (2H, m, 4-CH and3-CH), 2.07-2.22 (1H, m, 3-CH), 2.61 (1H, d, J=10.6, 6-CH), 3.41 (1H, t,J=8.2, 2-CH), 3.67 (1H, d, J=12.6), 3.64-3.73 (1H, m, 5-CH), 4.22 (1H,d, J=12.6), 4.75 (1H, sept, J=6.3), 6.73 (1H, s, OH), 7.2-7.4 (5H, m).

Spectrum data of isopropyl(2S,5R)-1-benzyl-5-[(S)-2-hydroxy-2-methyl-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 2b);

IR (neat): 1735, 1720 cm⁻¹.

NMR: 1.12 (3H, d, J=6.3), 1.13 (3H, d, J=6.3), 1.26 (3H, s), 1.41 (3H,s), 1.49 (9H, s), 1.79-1.91 (1H, m, 4CH), 1.92-2.01 (2H, m, 3-CH₂), 2.13(1H, m, 4-CH), 2.79 (1H, d, J=5.9, 6-CH₂), 3.37 (1H, t, J=7.2, 2-CH),3.50 (1H, dt, J=7.8, 6, 5-CH), 3.67 (1H, d, J=13.6), 4.08 (1H, d,J=13.6), 4.84 (1H, sept, J=6.3), 5.40 (1H, s, OH), 7.2-7.35 (5H, m).(Compound 4)

EXAMPLE 6 SYNTHESIS OF METHYL(2-5R)-1-BENZYL-5-[2-HYDROXY-2-METHYL-1-(t-BUTOXYCARBONYL)PROPYL]PYRROLIDINE-2-CARBOXYLATE(Compound 4) ##STR15##

In the same manner as in Example 11, methyl(2S,5R)-1-benzyl-5-(t-butoxycarbonyl) pyrrolidine-2-carboxylate(Compound 3, 199 rag, 0.60 mmol) was reacted with acetone (0.058 ml,0.79 mmol).

The reaction mixture was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetate-hexane 1:5) to recover theunreacted starting material (Compound 3, 115 mg, 58%) as well as toobtain a mixture of the two isomers of Compound 4 (Compound 4a,colorless viscous material, 10 mg, 5% and Compound 4b, colorless viscousmaterial, 40 mg, 17%).

Spectrum data of methyl(2S,5R)-1-benzyl-5-[(R)-2-hydroxy-2-methyl-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 4a);

NMR: 1.25 (3H, s), 1.42 (3H, s), 1.47 (9H, s), 1.65-1.75 (1H, m, 4-CH),1.89-2.20 (3H, m, 3-CH₂ and 4-CH), 2.59 (1H, d, J=10.0, 6-CH) , 3.42(3H, s) , 3.45 (1H, t, J=7.5, 2CH), 3.61-3.7 (1H, m, 5-CH), 3.68 (1H, d,J=12.8), 4.22 (1H, d, J=12.8), 7.2-7.4 (5H, m).

Spectrum data of methyl(2S,5R)-1-benzyl-5-[(S)-2-hydroxy-2-methyl-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 4b);

NMR: 1.24 (3H, s), 1.38 (3H, s), 1.50 (9H, s), 1.79-2.11 (4H, m, 3-CH₂and 4-CH₂), 2.69 (1H, d, J=6.1, 6-CH), 3.41 (1H, t, J=7.3, 2-CH), 3.50(3H, s), 3.55 (1H, m, 5CH), 3.68 (1H, d, J=13.7), 4.07 (1H, d, J=13.7),5.29 (1H, s, OH), 7.2-7.35 (5H, m).

EXAMPLE 7 SYNTHESIS OF ISOPROPYL(2S,5R)-1-BENZYL-5-[2-HYDROXY-2-METHYL-1-(METHOXYCARBONYL)PROPYL]PYRROLIDINE-2-CARBOXYLATE(Compound 6) ##STR16##

In the same manner as in Example 11, isopropyl(2S,5R)-1-benzyl-5-(methoxycarbonyl) pyrrolidine-2-carboxylate (Compound5, 208 mg, 0.65 mmol) was reacted with acetone (0. 062 ml, 0.84 mmol).The reaction mixture was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetate-hexane 1:5) to recover theunreacted starting material (Compound 5, 100 mg, 48%) as well as toobtain a mixture of the two isomers of Compound 6 (Compound 6a,colorless viscous material, 15 mg, 6% and Compound 6b, colorless viscousmaterial, 99 mg, 40%). Spectrum data of isopropyl(2S,5R)-1-benzyl-5-[(R)-2-hydroxy-2-methyl-1-(methoxycarbonyl)propyl]pyrrolidine-2-carboxylate (Compound6a);

NMR: 1.01 (3H, d, J=6.3), 1.06 (3H, d, J=6.2), 1.22 (3H, s), 1.44 (3H,s), 1.57-1.68 (1H, m, 4-CH), 1.89-2.06 (2H, m, 3-CH and 4-CH), 2.10-2.21(1H, m, 3-CH), 2.76 (1H, d, J=10.3, 6-CH), 3.41 (1H, t, J=8.1, 2-CH),3.66 (1H, d, J=12.5), 3.70 (3H, s), 3.65-3.76 (1H, m, 5-CH), 4.23 (1H,d, J=12.5), 4.75 (1H, sept, J=6.3), 6.62 (1H, s, OH), 7.2-7.4 (5H, m).

Spectrum data of isopropyl(2S,5R)-1-benzyl-5-[(S)-2-hydroxy-2-methyl-1-(methoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 6b);

NMR: 1.06 (3H, d, J=6.2), 1.10 (3H, d, J=6.3), 1.23 (3H, s), 1.32 (3H,s), 1.89-2.08 (4H, m, 3-CH₂ and 4-CH₂), 2.76 (1H, d, J=7.1, 6-CH), 3.32(1H, m, 2-CH), 353-3.63 (1H, m, 5-CH), 3.60 (1H, d, J=13.4), 3.75 (3H,s), 4.09 (1H, d, J=13.4), 4.49 (1H, s, OH), 4.77 (1H, sept, J=6.3),7.2-7.35 (5H, m).

EXAMPLE 8

In the same manner as in Example 11, Compound 1 (202 mg, 0.56 mmol) wasreacted, except that toluene was used as the reaction solvent.

The unreacted starting material was recovered in a 80 recovery rate, andCompound 2 was obtained in a 15% yield (Compounds 2a and 2b, 1:3).

EXAMPLE 9

In the same manner as in Example 11, Compound 1 (210 mg, 0.58 mmol) wasreacted, except that prior to adding Compound 1 to a lithiumdiisopropylamide solution, N,N,N',N'-tetramethylethylenediamine (0.105ml, 0.70 mmol) was added.

The unreacted starting material was recovered in a 50 recovery rate, andCompound 2 was obtained in a 45% yield (Compounds 2a and 2b, 1:3).

EXAMPLE 10 Synthesis of Methyl(2S,5R)-1-Benzyl-5-[2-Hydroxy-1-(t-Butoxycarbonyl)Propyl]Pyrrolidine-2-Carboxylate(Compound 7) ##STR17##

Under an argon atmosphere, n-butyl lithium (1.68M/hexane, 7.9 ml, 13.3mmol) was added dropwise to a THF (100 ml) solution of diisopropylamine(2.0 ml, 14 mmol) at -70° C., and the mixture was stirred for 35minutes. To the solution was added dropwise a THF (20 ml) solution ofCompound 3 (4.00 g, 12.0 mmol) at -70° C. and the mixture was stirredfor 20 minutes. Then, a THF (15 ml) solution of acetaldehyde (about 2ml, 40 mmol) was added dropwise and the mixture was stirred for 1.5hours.

The reaction was stopped by adding 16 ml of water. The reaction mixturewas extracted with ethyl acetate, and the ethyl acetate solution waswashed with an aqueous NaCl-saturated solution and dried over anhydroussodium sulfate. The solvent was removed by distillation under reducedpressure. The residue was purified by a medium pressure silica gelcolumn chromatography (Lobar size C, ethyl acetate-hexane 1 : 4) torecover the unreacted starting material (Compound 3, 1.41 g, 42%) aswell as to obtain a mixture of two isomers of Compound 7 (Compounds 7aand 7b (2:1), colorless viscous liquid, 1.91 g, 42%).

Spectrum data of methyl(2S,5R)-1-benzyl-5-[(1R,2R)-2-hydroxy-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 7a);

Mass spectrum m/z=377 (M⁺) .

IR (neat): 3506, 1729 cm⁻¹.

NMR: 1.29 (3H, d, J=6.6), 1.49 (9H, s), 1.70-2.10 (4H, m, 3-CH₂ and4-CH₂), 2.55 (1H, dd J=8.8 3.6 6-CH), 3.38-3.45 (1H, m, 2-CH), 3.44 (3H,s), 3.51 (1H, m, 5-CH), 3.75 (1H, d, J=13.4), 3.90-4.0 (1H, br-d, OH),4.22 (1H, d, J=13.4), 4.28 (1H, m, 8-CH), 7.2-7.4 (5H, m).

Spectrum data of methyl (2S,5R)-1-benzyl-5-[(1S,2S)-2-hydroxy-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 7b);

NMR (part): 1.24 (3H, d, J=6.6), 1.46 (9H, s), 2.46 (1H, dd, J=7.6, 3.0,6-CH), 3.51 (3H, s), 3.70 (1H, d, J=14.0), 3.94 (1H, d, J=14.0), 4.10(1H, br, 8-CH).

EXAMPLE 11

In the same manner as in Example 16, Compound 3 (690 mg, 2.07 mmol) wasreacted with a large excess of acetaldehyde. The unreacted startingmaterial (Compound 3, 206 mg, 30%) was recovered and also a mixture oftwo isomers of Compound 7 (Compounds 7a and 7b (4:1), 340 mg, 43.5%) anda third isomer (Compound 7c, 75 mg, 10%) were obtained.

Spectrum data of Compound 7c;

NMR: 1.24 (3H, d, J=6.0), 1.45 (9H, s), 1.82-2.14 (3H, m, 3-CH₂ and4-CH), 2.18-2.30 (1H, m, 4-CH), 2.70 (1H, dd, J=10.0, 2.8, 6-CH), 3.28(1H, m, 5-CH), 3.39 (1H, dd, J=8.5, 6.6, 2-CH), 3.44 (3H, s), 3.59 (1H,d, J=13.0), 4.10 (1H, d, J=13.0), 4.32 (1H, m, 8-CH), 6.51 (1H, s, OH),7.2-7.4 (SH, m).

EXAMPLE 12

In the same manner as in Example 16, Compound 3 (100 mg, 0.30 mmol) wasreacted, except that prior to adding Compound 3 to a lithiumdiisopropylamide solution, hexamethylphosphorictriamide (0.06 ml) wasadded.

A mixture of the two isomers of Compound 7 (Compounds 7a and 7b (3:1),20 mg, 18%) was obtained.

EXAMPLE 13

In the same manner as in Example 16, Compound 3 (2.00 g, 6.00 mmol) wasreacted, except that prior to adding acetaldehyde, diethylzinc (6.0mmol) was added and the mixture was stirred for 30 minutes.

A mixture of the two isomers of Compound 7 (Compounds 7a and 7b (3:1),707 mg, 31%) was obtained.

EXAMPLE 14

The procedure was the same as in Example 16, except that lithiumhexamethyldisilazide was used as the base. That is, under an argonatmosphere, n-butyl lithium (1.56M/hexane, 2.1 ml, 3.3 mmol) was addeddropwise to a THF (25 ml) solution of hexamethyldisilazane (0.76 ml, 3.6mmol) at -70° C., and the mixture was stirred for 35 minutes. To thesolution was added dropwise a THF (7 ml) solution of Compound 3 (1.00 g,3.0 mmol) at -70° C., and the mixture was stirred for one hour.Subsequently, a THF (5 ml) solution of acetaldehyde (about 0.7 ml, 13mmol) was added dropwise and the mixture was stirred for 2 hours.

The reaction was stopped by adding 15 ml of water. The reaction mixturewas extracted with ethyl acetate, and the ethyl acetate solution waswashed with an aqueous NaCl-saturated solution and dried over anhydroussodium sulfate. The solvent was removed by distillation under reducedpressure. The residue was purified by a medium pressure silica gelcolumn chromatography (Lobar size B, ethyl acetate-hexane 1:5) torecover the unreacted starting material (Compound 3, 657 mg, 66%) aswell as to obtain a mixture of the two isomers of Compound 7 (Compounds7a and 7b (1:1), 110 mg, 10%).

EXAMPLE 15

The procedure was the same as in Example 16, except that potassiumhexamethyldisilazide was used as the base. That is, under an argonatmosphere, to a THF (2 ml) solution of potassium hexamethyldisilazide(0.5 M/toluene, 0.72 ml, 0.36 mmol) was added dropwise a THF (1.5 ml)solution of Compound 3 (100 mg, 0.30 mmol) at -70° C., and the mixturewas stirred for 50 minutes. Subsequently, a THF (1.5 ml) solution ofacetaldehyde (about 0.1 ml, 2 mmol) was added dropwise thereto and themixture was stirred for 2.5 hours.

The reaction was stopped by adding 12 ml of water. The reaction mixturewas extracted with ethyl acetate, and the ethyl acetate solution waswashed with an aqueous NaCl-saturated solution and dried over anhydroussodium sulfate. The solvent was removed by distillation under reducedpressure. The residue was purified by a medium pressure silica gelcolumn chromatography (Lobar size A, ethyl acetate-hexane 1:5) torecover the unreacted starting material (Compound 3, 62 g, 62%) as wellas to obtain a mixture of the two isomers of Compound 7 (Compounds 7aand 7b (9:10), 19 mg, 17%).

EXAMPLE 16 Synthesis of Isopropyl(2S,5R)-1-Benzyl-5-[2-Hydroxy-1-(t-Butoxycarbonyl)Propyl]Pyrrolidine-2-Carboxylate(Compound 8) ##STR18##

Under an argon atmosphere, n-butyl lithium (1.6M/hexane, 11.5 ml, 18.4mmol) was added dropwise to a THF (70 ml) solution of diisopropylamine(2.8 ml, 20 mmol) at -70° C., and the mixture was stirred for 30minutes. To the solution was added dropwise a THF (15 ml) solution ofCompound 1 (6.03 g, 16.7 mmol), and the mixture was stirred for 50minutes. Subsequently, a THF (7 ml) solution of acetaldehyde (2 ml, 36mmol) was added dropwise thereto, and the mixture was stirred for onehour.

The reaction was stopped by adding 10 ml of an aqueous 20% ammoniumchloride solution. The reaction mixture was extracted with ethylacetate, and the ethyl acetate solution was washed with an aqueousNaCl-saturated solution and dried over anhydrous sodium sulfate. Thesolvent was removed by distillation under reduced pressure. The residuewas purified by a medium pressure silica gel column chromatography(Lobar size C, ethyl acetate-hexane 1:4, divided into two) to obtain anisomer of Compound 8 (Compound 8a, colorless viscous liquid, 0.40 g, 6%)and a mixture of the three isomers (Compounds 8a, 8b and 8c (24:59:17),pale yellow viscous liquid, 5.70 g, 84%).

Spectrum data of isopropyl (2S,5R)-1-benzyl-5-[(1R,2R)-2-hydroxy-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 8a);

IR (neat): 3423, 1727 cm⁻¹.

NMR: 1.05 (3H, d, J=6.3), 1.10 (3H, d, J=6.3), 1.29 (3H, d, J=6.6,9-CH₃), 1.49 (9H, s), 1.68-1.80 (1H, m, 4-CH), 1.84-1.99 (2H, m, 3-CHand 4-CH), 2.00-2.11 (1H, m, 3-CH), 2.55 (1H, dd, J=9.0, 3.3, 6-CH),3.39 (1H, t, J=7.5, 2-CH), 3.55 (1H, ddd, J=9.0, 7.1, 4.1, 5-CH), 3.76(1H, d, J=13.5), 4.04 (1H, br, OH), 4.22 (1H, d, J=13.5), 4.30 (1H, br,8-CH), 4.79 (1H, sept, J=6.3), 7.2-7.35 (5H, m).

Spectrum data of isopropyl (2S,5R)-1-benzyl-5-[(1S,2R)-2-hydroxy-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 8b);

IR (neat): 3342, 1727 cm⁻¹.

NMR: 1.07 (3H, d, J=6.6), 1.10 (3H, d, J=6.3), 1.24 (3H, d, J=6.0,9-CH₃), 1.45 (9H, s), 1.80-2.11 (3H, m, 3-CH₂ and 4-CH), 2.15-2.29 (1H,m, 4-CH), 2.69 (1H, dd, J=10.0, 3.0, 6-CH), 3.27 (1H, ddd, J=8.4, 6.9,3.0, 5-CH), 3.36 (1H, dd, J=8.9, 5.6, 2-CH), 3.60 (1H, d, J=13.2), 4.08(1H, d, J=13.2), 4.13 (1H, dq, J=10.0, 6.0, 8-CH), 4.79 (1H, sept,J=6.3), 6.36 (1H, s, OH), 7.2-7.4 (5H, m).

Spectrum data of isopropyl (2S,5R)-1-benzyl-5-[(1S,2S)-2-hydroxy-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 8c);

NMR (part): 1.10 (3H, d, J=6), 1.16 (3H, d, J=6.3), 1.25 (3H, d, J=6,9-CH₃), 1.45 (9H, s), 2.48 (1H, dd, J=7.7, 3.2, 6-CH), 3.46 (1H, m,5-CH), 3.70 (1H, d, J=14.1), 3.92 (1H, d, J=14.1), 4.10 (1H, br, 8-CH),4.86 (1H, sept, J=6.3), 7.2-7.4 (5H, m).

EXAMPLE 17 Synthesis of Isopropyl(2S,5R)-1-Benzyl-5-[2-Hydroxy-1-(T-Butoxycarbonyl)Butyl]Pyrrolidine-2-Carboxylate(Compound 9) ##STR19##

In the same manner as in Example 11, Compound 1 (365 mg, 1.01 mmol) wasreacted with propionaldehyde (0.10 ml, 1.4 mmol).

The reaction mixture was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetate-hexane 1:6) to recover theunreacted starting material (Compound 1, 93 mg, 26%) as well as toobtain an isomer of Compound 9 (Compound 9a, colorless viscous material,52 mg, 12%) and a mixture of the two other isomers (Compounds 9b and 9c(79:21), colorless viscous material, 211 mg, 50%).

Spectrum data of isopropyl (2S,5R)-1-benzyl-5-[(1R,2R)-2-hydroxy-1-(t-butoxycarbonyl)butyl]pyrrolidine-2-carboxylate(Compound 9a);

Mass spectrum m/z=419 (M⁺).

IR (neat): 3417, 1727 cm⁻¹.

NMR: 1.02 (3H, d, J=7.4), 1.06 (3H, d, J=6.0), 1.11 (3H, d, J=6.3), 1.48(9H, s), 1.45-1.6 (2H, m, 9-CH₂), 1.68-1.81 (1H, m, 4-CH), 1.82-2.10(3-CH₂ and 4-CH), 2.57 (1H, d, J=9.0, 3.0, 6CH), 3.39 (1H, t, J=7.2,2-CH), 3.54 (1H, ddd, J=9.0, 7.0, 4.4, 5-CH), 3.49-3.64 (1H, br, OH),3.78 (1H, d, J=13.5), 3.97 (1H, br, 8-CH), 4.22 (1H, d, J=13.5), 4.80(1H, sept, J=6.3), 7.2-7.35 (5H, m).

Spectrum data of isopropyl (2S,5R)-1-benzyl-5-[(1S,2R)-2-hydroxy-1-(t-butoxycarbonyl)butyl]pyrrolidine-2-carboxylate(Compound 9b);

NMR: 1.02 (3H, d, J=7.5), 1.08 (3H, d, J=6.3), 1.12 (3H, d, J=6.3), 1.44(9H, s), 1.4-1.65 (2H, m, 9-CH₂), 1.80-2.10 (3H, m, 3-CH₂ and 4-CH),2.23 (1H, 4-CH), 2.76 (1H, dd, J=10.2, 3.0, 6-CH), 3.25 (1H, ddd, J=8.6,7.4, 3.0, 5-CH), 3.55 (1H, dd, J=8.7, 5.5, 2-CH), 3.63 (1H, d, J=13.2),4.05 (1H, d, J=13.2), 4.12 (1H, ddd, J=10.2, 7.5, 2.7, 8-CH), 4.82 (1H,sept, J=6.3), 6.26 (1H, br, OH), 7.2-7.35 (5H, m).

Spectrum data of isopropyl (2S,5R)-1-benzyl-5-[(1S,S)-2-hydroxy-1-(t-butoxycarbonyl)butyl]pyrrolidine-2-carboxylate(Compound 9c);

NMR (part): 0.98 (3H, d, J=7.5), 1.11 (3H, d, J=6.3), 1.17 (3H, d,J=6.3), 1.43 (9H, s), 2.55 (1H, dd, J=7.8, 2.7, 6-CH), 3.69 (1H, d,J=14.0), 3.93 (1H, d, J=14.0), 4.86 (1H, sept, J=6.3).

EXAMPLE 18 Synthesis of Isopropyl(2S,5R)-1-Benzyl-5-[2-Hydroxy-2-Phenyl-1-(T-Butoxycarbonyl)Ethyl]Pyrrolidine-2-Carboxylate(Compound 10) ##STR20##

In the same manner as in Example 11, Compound 1 (365 mg, 1.01 mmol) wasreacted with benzaldehyde (0.14 ml, 1.4 mmol).

The reaction mixture was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetate-hexane 1:6) to recover theunreacted starting material (Compound 1, 65 mg, 18%) as well as toobtain a mixture of three isomers of Compound 10 (Compounds 10a, 10b and10c (13:27:60), colorless viscous material, 325 mg, Spectrum data of anisomer of isopropyl(2S,5R)-1-benzyl-5-[(1R)-2-hydroxy-2-phenyl-1-(t-butoxycarbonyl)ethyl]pyrrolidine-2-carboxylate(Compound 10a);

NMR: 1.09 (3H, d, J=6.0), 1.14 (3H, d, J=6.3), 1.27 (9H, s), 1.81-2.14(4H, m, 3-CH₂ and 4-CH₂), 2.88 (1H, dd, J=8.7, 3.9, 6-CH), 3.35-3.48(2H, m, 2-CH and 5-CH), 3.83 (1H, d, J=13.5), 3.99 (1H, br, OH), 4.18(1H, d, J=13.5), 4.85 (1H, sept, J=6.3), 5.32 (1H, br, 8-CH), 7.15-7.45(10H, m).

Spectrum data of an isomer of isopropyl(2S,5R)-1-benzyl-5-[(1S)-2-hydroxy-2-phenyl-1-(t-butoxycarbonyl)ethyl]pyrrolidine-2-carboxylate(Compound 10b);

NMR: 1.11 (3H, d, J=6.3), 1.15 (9H, s), 1.17 (3H, d, J=6.0), 1.94-2.15(4H, m, 3-CH₂ and 4-CH₂), 2.92 (1H, dd, J=8.0, 2.9, 6-CH), 3.39 (1H, dd,J=7.2, 5.4, 2-CH), 3.62 (1H, dr, J=8.0, ca. 7, 5-CH), 3.72 (1H, d,J=14.3), 3.97 (1H, d, J=14.3), 4.38 (1H, br-d, J=ca. 10, OH), 4.88 (1H,sept, J=6.3), 5.12 (1H, br-m, 8-CH), 7.15-7.45 (10H, m).

Spectrum data of the other isomer of isopropyl(2S,5R)-1-benzyl-5-[(1S)-2-hydroxy-2-phenyl-1-(t-butoxycarbonyl)ethyl]pyrrolidine-2-carboxylate(Compound 10c);

NMR: 1.0 (3H, d, J=6.3), 1.11 (3H, d, J=6.3 ), 1.13 (9H, s), 1.94-2.20(3H, m, 3-CH₂ and 4-CH), 2.36-2.50 (1H, m, 4-CH), 3.06 (1H, dd, J=10.2,3.3, 6-CH), 3.36 (1H, ddd, J=ca. 8, ca. 7, 3.3, 5-CH), 3.42 (1H, dd,J=8.7, 5.7, 2-CH), 3.72 (1H, d, J=12.9), 4.14 (1H, d, J=12.9), 4.83 (1H,sept, J=6.3), 5.13 (1H, d, J=10.2, 8-CH), 6.77 (1H, s, OH), 7.2-7.45(10H, m).

EXAMPLE 19 Synthesis of Isopropyl(2S,5R)-1-Benzyl-5-[2-Hydroxy-2-(2-Furyl)-1-(t-Butoxycarbonyl)Ethyl]Pyrrolidine-2-Carboxylate(Compound 11) ##STR21##

In the same manner as in Example 11, Compound 1 (365 mg, 1.01 mmol) wasreacted with furfural (0.116 ml, 1.4 mmol).

The reaction mixture was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetate-hexane 1:6) to recover theunreacted starting material (Compound 1, 27 mg, 7%) as well as to obtaina mixture of two isomers of Compound 11 (Compounds 11a and 11b (56: 44),colorless viscous material, 109 mg, 24%) and the other isomer (Compound11c, colorless viscous material, 223 mg, 48%).

Spectrum data of Compound 11a;

NMR: 1.11 (3H, d, J=6.3), 1.15 (3H, d, J=6.0), 1.37 (9H, s), 1.8-2.1(4H, m, 3-CH₂ and 4-CH₂), 3.05 (1H, dd, J=6.6, 2.7, 6-CH), 3.37 (1H, m,2-CH), 3.56 (1H, m, 5-CH), 3.69 (1H, d, J=13.7), 3.97 (1H, d, J=13.7),4.84 (1H, sept, J=6.3), 4.86 (1H, br, OH), 5.25 (1H, br, 8-CH),6.23-6.33 (2H, m), 7.2-7.4 (6H, m).

Spectrum data of Compound 11b;

NMR: 1.05 (3H, d, J=6.3), 1.10 (3H, d, J=6.3), 1.42 (9H, s), 1.8-2.1(4H, m, 3-CH₂ and 4-CH₂), 2.98 (1H, dd, J=9.6, 3.9, 6-CH), 3.37 (1H, m,2-CH), 3.56 (1H, m, 5-CH), 3.72 (1H, d, J=13.4), 4.13 (1H, d, J=13.4),4.79 (1H, sept, J=6.3), 5.06 (1H, br, OH), 5.32 (1H, br, 8-CH),6.23-6.33 (2H, m), 7.2-7.4 (6H, m).

Spectrum data of Compound 11c;

IR (neat): 3277, 1728 cm⁻¹.

NMR: 1.09 (3H, d, J=6.0), 1.10 (3H, d, J=6.3), 1.26 (9H, s), 1.87-2.35(4H, m, 3-CH₂ and 4-CH₂), 3.35-3.45 (3H, m, 2-CH and 5-CH and 6-CH),3.68 (1H, d, J=13.2), 4.18 (1H, d, J=13.2), 4.80 (1H, sept, J=6.3), 5.25(1H, d, J=10.2, 8-CH), 6.27-6.33 (2H, m), 6.77 (1H, s, OH), 7.2-7.4 (6H,m).

EXAMPLE 20 Synthesis of Isopropyl(2S,5R)-1-Benzyl-5-[2-Hydroxy-2-(2-Pyridyl)-1-(t-Butoxycarbonyl)Ethyl]Pyrrolidine-2-Carboxylate(Compound 12) ##STR22##

In the same manner as in Example 11, Compound 1 (365 mg, 1.01 mmol) wasreacted with pyridine-2-carboxaldehyde (0.135 ml, 1.4 mmol).

The reaction mixture was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetate-hexane 1:6→1:1) to recoverthe unreacted starting material (Compound 1, 64 mg, 18%) as well as toobtain a mixture of two isomers of Compound 12 (Compounds 12a and 12b(61:39), colorless viscous material, 125 mg, 26%) and other two isomers(Compounds 12c, yellow viscous material, 156 mg, 33% and Compounds 12d,yellow viscous material, 29 mg, 6%).

Spectrum data of Compound 12a;

NMR: 1.07 (3H, d, J=6.3), 1.14 (3H, d, J=6.3), 1.17 (9H, s), 1.9-2.3(4H, m, 3-CH₂ and 4-CH₂), 3.21 (1H, dd, J=6.8, 2.6, 6-CH), 3.41 (1H, dd,J=7.8, 5.4, 2-CH), 3.64 (1H, m, 5-CH), 3.74 (1H, d, J=14.1), 4.07 (1H,d, J=14.1), 4.84 (1H, sept, J=6.3), 5.17 (1H, br, OH), 5.33 (1H, br,8-CH), 7.17.4 (7H, m), 7.64 (1H, m), 8.50 (1H, m).

Spectrum data of Compound 12b;

NMR: 1.05 (3H, d, J=6.3), 1.11 (3H, d, J=6.3), 1.23 (9H, s), 1.8-2.3(4H, m, 3-CH₂ and 4-CH₂), 3.06 (1H, dd, J=8.1, 3.3, 6-CH), 3.42 (1H,2-CH), 3.72 (1H, m, 5-CH), 3.76 (1H, d, J=13.4), 4.21 (1H, d, J=13.4),4.80 (1H, sept, J=6.3), 5.21 (1H, br, OH), 5.46 (1H, br, 8-CH), 7.1-7.4(6H, m), 7.58 (1H, m), 7.68 (1H, m), 8.53 (1H, m).

Spectrum data of Compound 12c;

IR (neat): 3282, 1727 cm⁻¹.

NMR: 1.10 (3H, d, J=6.3), 1.11 (3H, d, J=6.3), 1.22 (9H, s), 1.89-2.18(3H, m, 3-CH₂ and 4-CH), 2.30-2.43 (1H, m, 4-CH), 3.42 (1H, dd, J=8.7,6.0, 2-CH), 3.47 (1H, m, 5-CH), 3.50 (1H, dd, J=10.2, 3.3, 6-CH), 3.72(1H, d, J=13.2), 4.19 (1H, d, J=13.2), 4.83 (1H, sept, J=6.3), 5.31 (1H,d, J=10.2, 8-CH), 6.91 (1H, br, OH), 7.17 (1H, m), 7.2-7.4 (5H, m), 7.49(1H, m), 7.67 (1H, m), 8.55 (1H, m).

Spectrum data of Compound 12d;

IR (neat): 3400, 1725 cm⁻¹.

NMR: 1.06 (3H, d, J=6.0), 1.10 (3H, d, J=6.3), 1.17 (9H, s), 1.77-1.85(1H, m, 4-CH), 1.90-2.08 (2H, m, 3-CH and 4-CH), 2.11-2.21 (1H, m,3-CH), 2.81 (1H, t, J=9.0, 6-CH), 3.45 (1H, t, J=8.0, 2-CH), 3.75 (1H,m, 5-CH), 3.77 (1H, d, J=12.5), 4.26 (1H, d, J=12.5), 4.78 (1H, sept,J=6.3), 5.09 (1H, d, J=9.0, 8-CH), 6.97 (1H, br, OH), 7.17 (1H, m),7.2-7.42 (5H, m), 7.55 (1H, m), 7.68 (1H, m), 8.52 (1H, m).

EXAMPLE 21 Synthesis of Isopropyl(2S,5R)-1-Benzyl-5-(t-Butoxycarbonylmethyl)Pyrrolidine-2-Carboxylate(Compound 1) ##STR23##

1) Under an argon atmosphere, n-butyl lithium (1.56M/hexane, 46.2 ml, 72mmol) was added dropwise to a THF (250 ml) solution of diisopropylamine(11.0 ml, 78.5 mmol) at -60° C. and the mixture was stirred at the sametemperature for 5 minutes and under ice-cooling for 20 minutes. To thesolution was added dropwise a THF (15 ml) solution of t-butyl acetate(9.7 ml, 72 mmol) at -65° C., and the mixture was stirred for 30minutes. Subsequently, a THF (25 ml) solution of isopropylN-benzyloxycarbonyl-L-pyrroglutamate was added dropwise and the mixturewas stirred for 60 minutes.

The reaction was stopped by adding 20 ml of an aqueous 20% ammoniumchloride solution, the organic layer was separated, the aqueous layerwas extracted with ethyl acetate, and the organic layers were combined,washed with NaCl-saturated water and dried. The solvent was removed bydistillation under reduced pressure. The solvent was sufficientlyremoved with a vacuum pump. Isopropyl(2S)-2-(benzyloxycarbonylamino)-6-(t-butoxycarbonyl)-5-oxohexanoate(Compound 13) was obtained as a pale yellowish viscous liquid (27.68 g,100%).

Spectrum date of Compound 13;

NMR: 1.20-1.30 (6H, m), 1.46 (9H, s), 1.85-1.99 (1H, m, 3-CH), 2.10-2.26(1H, m, 3-CH), 2.52-2.77 (2H, m, 4-CH₂), 3.33 (2H, s, 6-CH₂), 4.30 (1H,m, 2-CH), 4.97-5.1 (1H, m), 5.10 (2H, s), 5.37 (1H, br-d, NH), 7.25-7.4(5H, m).

2) Acetic acid (7.5 ml, 130 mmol) was added to an isopropyl alcohol (200ml) solution of Compound 13 (27.68 g, 65.5 mmol), and the mixture wassubjected to hydrogenolysis using 10% palladium carbon (650 mg) as thecatalyst at atmospheric pressure for 37 hours. Subsequently, platinumoxide (370 mg) was added and the mixture was reduced again with hydrogenunder atmospheric pressure for 128 hours (during this procedure, aceticacid (3.2 ml) and platinum oxide (100 mg) were further added).

The catalyst was filtered and the filtrate was concentrated to about 100ml under reduced pressure. Then, sodium hydrogen carbonate (30 g, 357mmol) and water (40 ml) were added to the residue and the mixture wasstirred. When evolution of a gas became weak, water (20 ml) was furtheradded. The remaining isopropyl alcohol was removed by distillation underreduced pressure, followed by addition of water (20 ml), and theresulting mixture was extracted with ethyl acetate. The ethyl acetatesolution was washed with an aqueous NaCl-saturated solution, and dried.The solvent was removed by distillation under reduced pressure.Isopropyl (2S,5R)-5-(t-butoxycarbonylmethyl)pyrrolidine-2-carboxylate(Compound 14) was obtained as a yellowish liquid (17.05 g, 96%).

Spectrum data of Compound 14;

IR (neat): 1730 cm⁻¹.

NMR: 1.24 (3H, d, J=6.3), 1.25 (3H, d, J=6.3), 1.45 (9H, s), 1.34-1.5(1H, m, 4-CH), 1.84-1.99 (2H, m, 3-CH and 4-CH), 2.02-2.15 (1H, m,3-CH), 2.42 (1H, dd, J=15.5, 6.2, 6-CH), 2.50 (1H, dd, J=15.5, 7.4,6-CH), 3.42 (1H, m, 5-CH), 3.72 (1H, dd, J=8.7, 5.7, 2-CH), 5.03 (1H,sept, J=6.3).

3) Under a dry atmosphere, triethylamine (9.6 ml, 69 mmol) was added toa dichloromethane (200 ml) solution of Compound 14 (17.0 g, 62.6 mmol),and a dichloromethane (20 ml) solution of benzyl bromide (9.0 ml, 76mmol) was also added dropwise at room temperature. The mixture wasstirred for 43 hours. During this procedure, benzyl bromide (0.75 ml)was further added two times.

The solvent was removed by distillation under reduced pressure, ethylacetate (200 ml) was added, and the mixture was washed with an aqueous5% sodium hydrogen carbonate solution and an aqueous NaCl-saturatedsolution, and dried. The solvent was removed by distillation underreduced pressure. The residue was purified by a silica gel columnchromatography (70 φ×160 mm, ethyl acetate-hexane 0:100→7:93) to obtainCompound 1 as a colorless liquid (19.58 g, 86%).

Spectrum data of Compound 1;

IR (neat): 1729 cm⁻¹.

NMR: 1.10 (3H, d, J=6.3), 1.15 (3H, d, J=6.3), 1.42 (9H, s), 1.62-1.75(1H, m, 4-CH), 1.81-2.08 (3H, m, 3-CH₂ and 4-CH), 2.24 (1H, dd, J=14.9,9.2, 6-CH), 2.54 (1H, dd, J=14.9, 4.4, 6-CH), 3.16 (1H, m, 5-CH), 3.30(1H, dd, J=7.9, 6.6, 2-CH), 3.77 (1H, d, J=14.0), 3.89 (1H, d, J=14.0),4.86 (1H, sept, J=6.3), 7.2-7.35 (5H, m).

EXAMPLE 22 Synthesis of Methyl(2S,5R)-1-Benzyl-5-(t-Butoxycarbonylmethyl)Pyrrolidine-2-Carboxylate(Compound 3) ##STR24##

1) In the same manner as in Example 27-1), methylN-benzyloxycarbonyl-L-pyrroglutamate was reacted with t-butyl acetate toobtain methyl(2S)-2-(benzyloxycarbonylamino)-6-(t-butoxycarbonyl)-5-oxohexanoate(Compound 15) as a pale yellowish viscous liquid (yield 90 to 100%).

Spectrum data of Compound 15;

NMR: 1.46 (9H, s), 1.87-2.01 (1H, m, 3-CH), 2.10-2.27 (1H, m, 3-CH),2.514-2.75 (2H, m, 4-CH₂), 3.33 (2H, s, 6-CH₂), 3.74 (3H, s), 4.35 (1H,m, 2-CH), 5.10 (2H, s), 5.39 (1H, br-d, NH), 7.25-7.4 (5H, m).

2) In the same manner as in Example 27-2), Compound (5.08 g, 12.9 mmol)was reacted, except that methanol was used as a solvent.

Methyl (2S,5R)-5-(t-butoxycarbonylmethyl)pyrrolidine-2-carboxylate(Compound 16) was obtained as a yellowish liquid (2.69 g, 86%).

Spectrum data of Compound 16;

NMR: 1.45 (9H, s), 1.33-1.5 (1H, m, 4-CH), 1.88-2.00 (2H, m, 3-CH and4-CH), 2.04-2.17 (1H, m, 3-CH), 2.44 (1H, dd, J=15.6, 6.0, 6-CH), 2.48(1H, dd, J=15.6, 7.2, 6-CH), 3.43 (1H, m, 5-CH), 3.72 (3H, s), 3.79 (1H,dd, J=9.0, 6.0, 2-CH).

3) In the same manner as in Example 27-3), Compound (622 mg, 2.56 mmol)was reacted (room temperature, 27 hours).

The product was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetate-hexane 1:5). Compound 3 wasobtained as a colorless liquid (649 mg, 76%).

Spectrum data of Compound 3;

Mass spectrum m/z=333 (M⁺).

IR (neat): 1729 cm⁻¹.

NMR: 1.43 (9H, s), 1.65-1.77 (1H, m, 4-CH), 1.84-2.08 (3H, m, 3-CH₂ and4-CH), 2.27 (1H, dd, J=14.8, 9.1, 6-CH), 2.58 (1H, dd, J=14.8, 4.3,6-CH), 3.14 (1H, m, 5-CH), 3.33 (1H, dd, J=ca.7, ca.8, 2-CH), 3.38 (3H,s), 3.70 (1H, d, J=13.9), 3.93 (1H, d, J=13.9), 7.2-7.35 (5H, m).

EXAMPLE 23 Synthesis of Isopropyl(2S,5R)-1-Benzyl-5-(Methoxycarbonylmethyl)Pyrrolidine-2-carboxylate(Compound 5) ##STR25##

1) In the same manner as in Example 27-1), isopropylN-benzyloxycarbonyl-L-pyrroglutamate (2.01 g, 6.58 mmol) was reactedwith methyl acetate.

2.46 g of a crude isopropyl(2S)-2-(benzyloxycarbonylamino)-6-(methoxycarbonyl)-5-oxohexanoate(Compound 17) product was obtained as a yellowish viscous liquid, (whichproduct contained about 9% of impurities and, as Compound 17, 2.28 g,91%).

Spectrum data of Compound 17;

IR (neat): 3359, 1723 cm⁻¹.

NMR: 1.22-1.30 (6H, m), 1.83-1.99 (1, m, 3-CH), 2.12-2.30 (1H, m, 3-CH),2.50-2.77 (2H, m, 4-CH₂), 3.44 (2H, s, 6-CH₂), 3.72 (3H, s), 4.30 (1H,m, 2-CH), 4.97-5.1 (1H, m), 5.11 (2H, s), 5.37 (1H, br-d, NH), 7.25-7.4(5H, m).

2) In the same manner as in Example 27-2), Compound 17 (2.46 g, asCompound 17, 2.28 g, 6.01 mmol) was reacted, except that when extractionwith ethyl acetate was carried out, NaCl and sodium hydrogen carbonatewere excessively added to an aqueous layer and the mixture wassufficiently extracted.

1.30 g of a crude isopropyl(2S,5R)-5-(methoxycarbonylmethyl)pyrrolidine-2-carboxylate (Compound 18)product was obtained as a yellowish liquid, (which product containedabout 21% of impurities and, as Compound 19, about 1.03 g, 74%).

Spectrum data of Compound 18;

NMR: 1.24 (3H, d, J=6.2), 1.25 (3H, d, J=6.4), 1.35-1.48 (1H, m, 4-CH),1.87-2.02 (2H, m, 3-CH and 4-CH), 2.04-2.17 (1H, m, 3-CH), 2.53 (1H, dd,J=15.8, 6.0, 6-CH), 2.58 (1H, dd, J=15.8, 7.5, 6-CH), 3.49 (1H, m,5-CH), 3.69 (3H, s), 3.74 (1H, dd, J=8.7, 5.6, 2-CH), 5.03 (1H, sept,J=6.3).

3) In the same manner as in Example 27-3), Compound 18 (1.30 g, asCompound 18, 1.03 g, 4.49 mmol) was reacted (room temperature, 28hours).

The product was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetatehexane 1:5). Compound 5 wasobtained as a colorless liquid. 1.228 g (86%).

Spectrum data of Compound 5;

IR (neat): 1735 cm⁻¹.

NMR: 1.11 (3H, d, J=6.3), 1.16 (3H, d, J=6.3), 1.62-1.74 (1H, m, 4-CH),1.82-2.10 (3H, m, 3-CH₂ and 4-CH), 2.35 (1H, dd, J=15.3, 9.0, 6-CH),2.58 (1H, dd, J=15.3, 4.5, 6-CH), 3.22 (1H, m, 5-CH), 3.33 (1H, dd,J=7.8, 6.7, 2-CH), 3.63 (3H, s), 3.83 (2H, ABq, J=14.0), 4.87 (1H, sept,J=6.3), 7.2-7.35 (5H, m).

In the following, a series of reaction steps (Reference example 1) forobtaining (5R,6R)-6-(2-hydroxy-2-propyl)-2-[(3S)-pyrrolidine-3-ylthio]-1-carba-2-penem-3-carboxylicacid (Compound S9) from isopropyl(2S,5R)-1-benzyl-5-[(R)-2-hydroxy-2-methyl-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 2a) and another series of reaction steps (Reference example 2)for obtaining p-nitrobenzyl(5R,6R)-6-[(R)-1-hydroxyethyl]-2-[(3S)-1-(p-nitrobenzyloxycarbonyl)pyrrolidine-3-ylthio]-1-carba-2-penem-3-carboxylate(Compound S16) from isopropyl(2S,5R)-1-benzyl-5-[(1S,2R)-2-hydroxy-1-(t-butoxycarbonyl)propyl]pyrrolidine-2-carboxylate(Compound 8b) are exemplified for reference purpose.

In addition to the abbreviations used in Examples 11 to 29, thefollowing are used.

DBU: 1,8-Diazabicyclo[5,4,0]-7-undecene

DMF: N,N-Dimethylformamide

PNB: Para-nitrobenzyl

PNZ: Para-nitrobenzyloxycarbonyl

REFERENCE EXAMPLE 1 (a) Synthesis of Isopropyl(3S,5R,6R)-6-(2-Hydroxy-2-Propyl)-1-Carbapenam-3-Carboxylate (CompoundS1) ##STR26##

Acetic acid (0.42 ml, 7.3 mmol) was added to a methanol (27 ml) solutionof a mixture of Compounds 2a and 2b (29:71), (3.08, 7.34 mmol), and themixture was subjected to hydrogenolysis using a 10% palladium carbon(120 mg) as the catalyst at atmospheric pressure for 7 hours.

The catalyst was removed by filtration, and the solvent was removed bydistillation under reduced pressure. The residue was dissolved in ethylacetate, and the solution was washed with an aqueous 5% sodium hydrogencarbonate solution. The aqueous layer was reverse-extracted with ethylacetate. The ethyl acetate solutions were combined, washed with anaqueous NaCl-saturated solution and dried, and the solvent was removedby distillation under reduced pressure. The N-deprotected material wasobtained as a pale yellowish viscous liquid. 2.33 g (96.5%).

Under a dry atmosphere, to a dichloromethane (3 ml) solution of thisN-deprotected material was added 4N hydrochloride/dioxane (30 ml) underice-cooling, and the mixture was stirred at room temperature for 23hours. The solvent was removed by distillation under reduced pressure,and hexane was added to the residue and removed by distillation underreduced pressure (three times). Evaporation with a vacuum pump gave apale yellowish foamy solid (2.56 g). Under a dry atmosphere, to adichloromethane (50 ml) solution of this foamy material were addedtriethylamine (1.3 ml, 9.3 mmol) and water-soluble carbodiimide(1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride (1.8 g,9.4 mmol) under ice-cooling, and the mixture was stirred at roomtemperature for 12.5 hours. The solvent was removed by distillationunder reduced pressure, water was added and the mixture was extractedwith ethyl acetate. The ethyl acetate solution was washed with anaqueous NaCl-saturated solution and dried, and the solvent was removedby distillation under reduced pressure.

The residue was divided into two portions. Each portion was purified bya medium pressure silica gel column chromatography (Lobar size B, ethylacetate-hexane 1:1) to obtain Compound S1 (pale yellowish fine needlecrystals, top. 69°-70.5° C., 416 mg, yield from Compound 2a, 77%), andthe 6-position isomer derived from Compound 2b ((3S,5R,6S)isomer, paleyellowish viscous liquid, 944 mg, yield from Compound 2b, 71% ).

Spectrum date of Compound S1;

IR (KBr): 3450, 3520, 1740, 1720 cm⁻¹.

NMR: 1.25 (3H, d, J=6.3), 1.27 (3H, s), 1.30 (3H, d, J=6.2), 1.47 (3H,s), 1.88 (1H, m, 1-CH), 2.23-2.33 (2H, m, 2-CH₂), 2.53 (1H, s, OH), 2.85(1H, m, 1-CH), 3.23 (1H, dd, J=5.1, 1.1, 6-CH), 3.77 (1H, dt, J=9.8,5.5, 5-CH), 3.89 (1H, m, 3-CH), 5.09 (1H, sept, J=6.3).

(b) Synthesis of Isopropyl(5R,6R)-6-(2-Hydroxy-2-Propyl)-3-Phenylseleno-1-Carbapenam-3-Carboxylate(Compound ##STR27##

Under an argon atmosphere, n-butyl lithium (1.6M/hexane, 1.9 ml, 3.0mmol) was added to a THF (9 ml) solution of diisopropylamine (0.46 ml,3.3 mmol) at -70° C., and the mixture was stirred for 30 minutes. To thesolution was added dropwise a THF (3 ml) solution of Compound S1 (308mg, 1.21 mmol) at -70° C., and the mixture was stirred for 26 minutes.Subsequently, a THF (2 ml) solution of phenylselenyl chloride (350 mg,1.8 mmol) was added dropwise and the mixture was stirred for 5 minutes.

The reaction was stopped by adding an aqueous 10% ammonium chloridesolution (18 ml). The reaction mixture was extracted with ethyl acetate,the ethyl acetate solution was washed with an aqueous NaCl-saturatedsolution and dried, and the solvent was removed by distillation underreduced pressure. The residue was purified by a medium pressure silicagel column chromatography (Lobar size B, ethyl acetate-hexane 1:2) toobtain a mixture of the two isomers of Compound S2 (78:22, yellowishviscous material, 343 mg, 69%).

Spectrum date of Compound S2;

NMR of low polarity isomer: 1.21 (3H, s), 1.27 (6H, d, J=6.3), 1.44 (3H,s), 1.80-1.93 (1H, m, 1-CH), 1.92 (1H, s, OH), 2.25-2.36 (1H, m, 2-CH),2.61-2.81 (2H, m, 1-CH and 2CH), 3.22 (1H, d, J=5.7, 6-CH), 3.53 (1H, m,5-CH), 5.09 (1H, sept, J=6.3), 7.25-7.4 (3H, m), 7.6-7.7 (2H, m).

NMR of high polarity isomer: 1.13 (3H, d, J=6.3), 1.14 (3H, d, J=6.3),1.29 (3H, s), 1.53 (3H, s), 1.81 (1H, s, OH), 1.85-1.96 (1H, m, 1-CH),2.40-2.59 (2H, m, 2-CH₂), 2.90 (1H, m, 1-CH), 3.25 (1H, d, J=5.4, 6-CH),3.87 (1H, m, 5-CH), 4.81 (1H, sept, J=6.3), 7.25-7.4 (3H, m), 7.7.-7.8(2H, m).

(c) Synthesis of Isopropyl(5R,6R)-6-(2-Hydroxy-2-Propyl-1-Carba-2-Penem-3-Carboxylate (CompoundS3) ##STR28##

Under an argon atmosphere, to a dichloromethane (10 ml) solution ofCompound S2 (two isomers (78:22), 343 mg, 0.836 mmol) was added dropwisea dichloromethane (3.5 ml) solution of meta-chloroperbenzoic acid (320mg, 1.8 mmol) at -30° C. and the mixture was stirred for 30 minutes.Subsequently, at the same temperature, triethylamine (0.35 ml, 2.5 mmol)was added dropwise and the mixture was stirred for 30 minutes.

The reaction mixture was diluted with ethyl acetate, washed with water,and the aqueous layer was reverse-extracted with ethyl acetate. Theethyl acetate solutions were combined, washed with an aqueousNaCl-saturated solution and dried, and the solvent was removed bydistillation under reduced pressure. The residue was purified by amedium pressure silica gel column chromatography (Lobar size B, ethylacetate-hexane 1:2→1:1) to obtain Compound S3 (colorless crystals, mp.108°-110° C., 149 mg, 70%).

Spectrum data of Compound S3;

IR (KBr): 3450, 1770, 1750, 1720, 1680 cm⁻¹.

NMR: 1.27 (3H, s), 1.31 (3H, d, J=6.3), 1.32 (3H, d, J=6.5), 1.51 (3H,s), 1.61 (1H, s, OH), 2.67 (1H, ddd, J=18.7, 10.1, 3.1, 1-CH), 3.59 (1H,d, J=6.1, 6-CH), 3.78 (1H, ddd, J=18.7, 9.0, 2.6, 1-CH), 4.32 (1H, ddd,J=10.1, 9.0, 6.1, 5-CH), 5.15 (1H, sept, J=6.3), 6.52 (1H, dd, J=3.1,2.6, 2-CH), minute coupling (<1 Hz) was admitted between 2-CH and 6-CH.

(d) Synthesis of Isopropyl(5R,6R)-6-(2-Hydroxy-2-Propyl)-2-Ethylthio-1-Carbapenam-3-Carboxylate(Compound S4) ##STR29##

Under a dry atmosphere, to a dichloromethane (9 ml) solution of CompoundS3 (149 mg, 0.588 mmol) were added ethanethiol (0.094 ml, 1.3 mmol) andDBU (0.040 ml, 0.27 mmol) at -30° C., and the mixture was stirred at thesame temperature for 80 minutes.

The reaction mixture was diluted with ethyl acetate, washed with anaqueous 5% citric acid solution, an aqueous sodium hydrogen carbonatesolution and an aqueous NaCl-saturated solution, and dried. The solventwas removed by distillation under reduced pressure to obtain a mixtureof two isomers of Compound S4 (71:29, pale yellowish viscous material,177 mg, 95%).

(e) Synthesis of p-Nitrobenzyl(5R,6R)-6-(2-Hydroxy-2-Propyl)-2-Ethylthio-1-Carbapenam-3-Carboxylate(Compound S5) ##STR30##

To a THF-water (2:1, 9 ml) solution of Compound S4 (two isomers (72:28),239 mg, 0.758 mmol) was added under ice-cooling an aqueous 1N sodiumhydroxide solution (0.758 ml, 0.758 mmol) in consecutive 5 portions atevery 8 minutes. The mixture was stirred under ice-cooling for 30minutes and at room temperature for 3 hours. Water (3 ml) was added, theTHF was removed by distillation under reduced pressure and the residualaqueous solution was washed with ether (from the ether solution,Compound S4 (72 mg, 30%) was recovered).

Water was removed by distillation under reduced pressure to dryness.Under a dry atmosphere, para-nitrobenzyl bromide (180 mg, 0.83 mmol) wasadded to a DMF (7 ml) solution of the residue (pale yellowish candy-likematerial), and the mixture was stirred at room temperature for 3.8hours. The DMF was removed by distillation under reduced pressure, theresidue was diluted with ethyl acetate and washed with an aqueousNaCl-semisaturated solution. The aqueous layer was reverse-extractedwith ethyl acetate, the ethyl acetate solutions were combined, washedwith an aqueous NaCl-saturated solution and dried, and the solvent wasremoved by distillation under reduced pressure. The residue was purifiedby a medium pressure silica gel column chromatography (Lobar size B,ethyl acetate-hexane 1:2→1:1) to obtain an isomer of Compound S5 (paleyellowish viscous material, 103 mg, 33%).

Spectrum data of Compound S5;

NMR: 1.22 (3H, t, J=7.5), 1.25 (3H, s), 1.48 (3H, s), 1.72 (1H, s, OH),2.34 (1H, m, 1-CH), 2.57 (2H, q, J=7.5, SCH₂), 2.87 (1H, ddd, J=12.8,11.8, 9.7, 1-CH), 3.42 (1H, d, J=5.4, 6-CH), 3.72 (1H, ddd, J=11.8, 8.7,6.5, 2-CH), 3.92 (1H, m, 5-CH), 4.22 (1H, d, J=8.7, 3-CH), 5.31 (2H,ABq, J=13.4), 7.56 (2H, d), 8.24 (2H, d).

(f) Synthesis of p-Nitrobenzyl(5R,6R)-6-(2-Hydroxy-2-Propyl)-2-Chloro-2-Ethanesulfinyl-1-Carbapenam-3-Carboxylate(Compound S6) ##STR31##

Under a dry atmosphere, to a dichloromethane (4 ml) solution of CompoundS5 (50 mg, 0.12 mmol) were added water (0.011 ml, 0.61 mmol) andpyridine (0.030 ml, 0.37 mmol), and further added dropwise adichloromethane (1.5 ml) solution of iodobenzene dichloride (84 mg, 0.31mmol) under ice-cooling, and the mixture was stirred at the sametemperature for 30 minutes. Subsequently, triethylamine (0.034 ml, 0.24mmol) was added and the mixture was stirred for 10 minutes.

The reaction mixture was diluted with ethyl acetate, washed with waterand an aqueous NaCl-saturated solution and dehydrated, and the solventwas removed by distillation under reduced pressure. The residue waspurified by a medium pressure silica gel column chromatography (Lobarsize A, ethyl acetate-hexane 1:1→1:0) to obtain a mixture (paleyellowish viscous material, 58 mg) of some isomers of Compound S6 and alittle amount of p-nitrobenzyl(5R,6R)-6-(2-hydroxy-2-propyl)-2-ethanesulfinyl-1-carba-2-penem-3-carboxylate(Compound S7).

The facts that Compound S6 is a mixture of the isomers and Compound S7is mixed therewith have no problem since these compounds are allconverted into the same compound in the next step.

(g) Synthesis of p-Nitrobenzyl(5R,6R)-6-(2-Hydroxy-2-Propyl)-2-[(3S)-1-(p-Nitrobenzyloxycarbonyl)Pyrrolidine-3-Ylthiol-1-Carba-2-Penem-Carboxylate(Compound S8) ##STR32##

Under an argon atmosphere, DBU (0.014 ml, 0.094 mmol) was added to a DMF(3 ml) solution of a mixture (44 mg, 50 mg obtained from Compound S5) ofCompounds S6 and S7 at -30° C., and the mixture was stirred for 34minutes. Subsequently, at the same temperature, a DMF (0.15 ml) solutionof (S)-3-mercapto-1-(p-nitrobenzyloxycarbonyl)pyrrolidine (33 mg, 0.12mmol) was added, and the mixture was stirred for 40 minutes.

An aqueous 5% citric acid solution was added, and the mixture wasextracted with ethyl acetate. The ethyl acetate solution was washed withan aqueous NaCl-semisaturated solution and an aqueous NaCl-saturatedsolution, and dried. The solvent was removed by distillation underreduced pressure. The residue was purified by a medium pressure silicagel column chromatography (Lobar size A, ethyl acetate-hexane 2:1) toobtain Compound S8. Yellowish viscous material, 41 mg. The materialcontained DMF (about 0.5 mg) and ethyl acetate (about 3.5 mg), and it is37 mg as Compound S8. Yield from Compound S5, 48%.

Spectrum data of Compound S8;

IR (neat): 3417, 1778, 1707 cm⁻¹.

NMR: 1.29 (3H, s), 1.54 (3H, s), 1.5-1.7 (br, OH), 1.93-2.09 (1H, br,4'-CH), 2.27-2.43 (1H, m, 4'-CH), 2.86-3.06 (1H, m, 1-CH), 3.43-3.59(1H, m), 3.60-3.72 (1H, m), 3.64 (1H, d, J=5.7, 6-CH), 3.74-3.92 (2H,m), 4.20-4.47 (2H, m, 1-CH and 5-CH), 5.23 (2H, s), 5.23 (1H, d,J=13.8), 5.51 (1H, d, J=13.8), 7.51 (2H, d), 7.66 (2H, d), 8.23 (4H, d).

(h) Synthesis of(5R,6R)-6-(2-Hydroxy-2-Propyl)-2-[(3S)-Pyrrolidine-3-Ylthio]-1-Carba-2-Penem-CarboxylicAcid (Compound S9) ##STR33##

To a phosphate buffer (0.1M, pH 7.0)-THF solution (6:5, 5.5 ml) ofCompound S8 (35.5 mg, 0.057 mmol) was added a 10% palladium carbon (18mg), and the mixture was subjected to hydrogenolysis at normal pressurefor 2.7 hours.

The palladium carbon was removed by filtration, the THF in the filtratewas removed by distillation under reduced pressure, and the residue waswashed with ethyl acetate. The residual ethyl acetate was removed bydistillation under reduced pressure. The residue was concentrated toabout a 5 ml volume under reduced pressure and purified by anion-exchange resin column chromatography ("Diaion HP-20", 15 φ×20 cm) at4° C. Elution (about 0.5 ml/min) was carried out, using pure water, anaqueous 10% methanol solution and an aqueous 20% methanol in this order.The fractions of the desired compound were concentrated to about a 5 mlvolume under reduced pressure and freeze-dried to obtain Compound S9(pale yellowish-white solid, 8.8 mg, 50%).

Spectrum data of Compound S8;

IR (KBr): 3425, 1756, 1599, 1383 cm⁻¹.

NMR (D20, internal standard TSP-d₄): 1.31 (3H, s), 1.44 (3H, s), 2.05(1H, m, 4'-CH), 2.49 (1H, m, 4'-CH), 3.07 (1H, dd, J=17.4, 10.2, 1-CH),3.30-3.43 (2H, m, 2'-CH and 5'-CH), 3.51 (1H, m, 5'-CH), 3.66 (1H, dd,J=12.6, 6.6, 2'-CH), 3.75 (1H, d, J=5.7, 6-CH), 3.90 (1H, dd, J=17.4,8.9, 1-CH), 4.05 (1H, m, 3'-CH), 4.33 (1H, ddd, J=10.2, 8.9, 5.7, 5-CH).

REFERENCE EXAMPLE 2 (a) Synthesis of Isopropyl(3S,5R,6S)-6-[(R)-1-Hydroxyethyl]-1-Carbapenam-3-Carboxylate (CompoundS10) ##STR34##

Acetic acid (0.85 ml, 14.9 mmol) was added to a methanol (55 ml)solution of a mixture of Compounds 8a, 8b and 8c (24:59: 17, 5.69 g,14.0 mmol), and the mixture was subjected to hydrogenolysis using a 10%palladium carbon (250 mg) as the catalyst at normal pressure for 3.8hours. The catalyst was removed by filtration, and the solvent wasremoved by distillaton under reduced pressure. The residue was dissolvedin ethyl acetate, the solution was washed with an aqueous 5% sodiumhydrogen carbonate solution. The aqueous layer was reverse-extractedwith ethyl acetate. The ethyl acetate solutions were combined, washedwith an aqueous NaCl-saturated solution and dried. The solvent wasremoved by distillation under reduced pressure. An N-deprotectedmaterial was obtained as a pale yellowish viscous liquid (4.17 g,94.2%).

Under a dry atmosphere, to a dichloromethane (10 ml) solution of thisN-deprotected material was added 4N hydrochloride/dioxane (50 ml) underice-cooling, and the mixture was stirred at room temperature for 21hours. The solvent was removed by distillation under reduced pressure,hexane was added to the residue and removed by distillation underreduced pressure. Further, hexane-dichloromethane was added to theresidue and removed by distillation under reduced pressure. Theatmosphere was in pressure reduced with a vacuum pump to give a paleyellowish foamy solid.

Under a dry atmosphere, to a dichloromethane (90 ml) solution of thisfoamy material were added triethylamine (2.4 ml, 18 mmol) andwater-soluble carbodiimide(1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride, 3.3 g,17 mmol) under ice-cooling, and the mixture was stirred at roomtemperature for 20 hours. The solvent was removed by distillation underreduced pressure, water was added and the mixture was extracted withethyl acetate. The ethyl acetate solution was washed with an aqueousNaCl-saturated solution and dried, and the solvent was removed bydistillation under reduced pressure.

The residue was divided into three portions, and each portion waspurified by a medium pressure silica gel column chromatography (Lobarsize B, ethyl acetate-hexane 7:5→2:1). There were obtained a carbapenam((6R,8R)-isomer, pale yellowish viscous liquid, 319 mg, 9.4%) derivedfrom Compound 8a, and a mixture (76:24, pale yellowish viscous liquid,2.06 g (containing about 5% of impurities), yield 58%. Yield of CompoundS10 from Compound 8b was 75%) of Compound S10 and a carbapenam((6S,8S)-isomer) derived from Compound 8c.

Spectrum data of Compound S10;

NMR: 1.26 (3H, d, J=6.0), 1.30 (3H, d, J=6.3), 1.32 (3H, d, J=6.3,9-CH₃), 1.78-1.93 (1H m, 1-CH), 2.07-2.17 (1H, m, 1-CH), 2.27-2.43 (2H,m, 2-CH₂), 3.02 (1H, dd, J=6.0, 2.4, 6-CH), 3.71 (1H, ddd, J=9.5, 5.6,2.4, 5-CH), 3.86 (1H, dd, J=6.6, 3.2, 3-CH), 4.19 (1H, m, 8-CH), 5.07(1H, sept, J=6.3).

(b) Synthesis of Isopropyl(5R,6S)-6-[(R)-1-Hydroxyethyl]-3-Phenylseleno-1-Carbapenam-3-Carboxylate(Compound S11) ##STR35##

Under an argon atmosphere, n-butyl lithium (1.6M/hexane, 7.8 ml, 12.5mmol) was added to a THF (35 ml) solution of diisopropylamine (1.92 ml,13.7 mmol) at -70° C., and the mixture was stirred for 40 minutes. Tothe solution was added dropwise a THF (6 ml) solution of a mixture ofCompound S10 and its (8S)-isomer (78:22, 1.20 g, 4.97 mmol, containingabout 5% of impurities) at -70° C., and the mixture was stirred for 35minutes. Subsequently, a THF (5 ml) solution of phenylselenyl chloride(1.43 g, 7.5 mmol) was added dropwise and the mixture was stirred for 8minutes.

The reaction was stopped by adding an aqueous 20% ammonium chloridesolution (18 ml). The reaction mixture was extracted with ethyl acetate,the ethyl acetate solution was washed with an aqueous NaCl-saturatedsolution and dried. The solvent was removed by distillation underreduced pressure. The residue was purified by a medium pressure silicagel column chromatography (Lobar size B, ethyl acetate-hexane 2:3→2:1)to obtain a mixture (78:22, yellowish viscous material, 1.04 g(containing about 5% of impurities), yield 50%) of a low polarity isomerof Compound S11 and its (8S)-isomer, and a mixture (72:28, 250 mg(containing about 5% of impurities), yield 11%) of a high polarityisomer of Compound S11 and its (8S)-isomer.

Spectrum data of Compound S11;

NMR of low polarity isomer: 1.27 (3H, d, J=6.3, 9-CH₃), 1.28 (6H, d,J=6.3), 1.29 (3H, d, J=6.3), 1.63 (1H, r-d, J=5, OH), 1 73-1.88 (1H, m,1-CH), 1.94 -2.07 (1H, m, 1-CH), 2.40 (1H, ddd, J=14.1, 9.8, 6.8, 2-CH),2.69 (1H, ddd, J=14.1, 7.7, 3.5, 2-CH), 2.90 (1H, dd, J=6.2, 2.2, 6-CH),3.32 (1H, ddd, J=8.1, 6.0, 2.2, 5-CH), 4.10 (1H, m, 8-CH), 5.08 (1H,sept, J=6.3), 7.25-7.45 (3H, m), 7.65-7.75 (2H, m).

NMR of high polarity isomer: 1.16 (6H, d, J=6.3), 1.34 (3H, d, J=6 39-CH₃), 1.60-1.70 (1H, m, 1-CH), 2.03-2.14 (1H, m, 1-CH), 2.49 (1H, ddd,J=14.3, 6.9, 2.3, 2-CH), 2.86 (1H, ddd, J=14.3, 11.7, 6.2, 2-CH), 2.96(1H, dd, J=6.8, 2.3, 6-CH), 3.81 (1H, ddd, J=9.0, 5.9, 2.3, 5-CH), 4.21(1H, m, 8-CH), 4.85 (1H, sept, J=6.3), 7.25-7.45 (3H, m), 7.7-7.8 (2H,m).

(c) Synthesis of Isopropyl(5R,6S)-6-[(R)-1-Hydroxyethyl]-1-Carba-2-Penem-3-Carboxylate (CompoundS12) ##STR36##

Under an argon atmosphere, to a dichloromethane (25 ml) solution of themixture of Compound S11 and the (8S)-isomer thereof obtained in thepreceding item (b) was added dropwise a dichloromethane (13 ml) solutionof meta-chloroperbenzoic acid (1.23 g, 6.8 mmol) at -30° C. and themixture was stirred for 35 minutes. Subsequently, at the sametemperature, triethylamine (1.35 ml, 9.7 mmol) was added dropwise andthe mixture was stirred for 32 minutes.

The reaction mixture was diluted with ethyl acetate, and washed withwater. The aqueous layer was reverse-extracted with ethyl acetate. Theethyl acetate solutions were combined, washed with an aqueousNaCl-saturated solution and dried, and the solvent was removed bydistillation under reduced pressure. The residue was purified by amedium pressure silica gel column chromatography (Lobar size B, ethylacetate-hexane 1:1→3:2) to obtain a mixture (78:22, yellowish viscousmaterial, 397 mg (containing about 5% of impurities), yield 51%) ofCompound S12 and the (8S)-isomer thereof.

Spectrum data of Compound S12;

NMR: 1.308 (3H, d, J=6.3), 1.311 (3H, d, J=6.3), 1.35 (3H, d, J=6.3,9-CH₃), 1.79 (1H, br-d, J=5, OH), 2.79 (1H, ddd, J=19.1, 8.3, 2.7,1-CH), 2.95 (1H, ddd, J=19.1, 10.0, 3.0, 1-CH), 3.19 (1H, dd, J=6.8,3.2, 6-CH), 4.25 (1H, m, 8-CH), 4.27 (1H, ddd, J=10.0, 8.3, 3.2, 5-CH),5.15 (1H, sept, J=6.3), 6.42 (1H, dd, J=3.0, 2.7, 2-CH). Small coupling(<1 Hz) was observed between 2-CH and 6-CH.

(d) Synthesis of Isopropyl(5R,6S)-6-[(R)-1-Hydroxyethyl]-2-Ethylthio-1-Carbapenam-3-Carboxylate(Compound S13) ##STR37##

Under a dry atmosphere, to a dichloromethane (10 ml) solution of amixture (86:14, 250 mg (containing about 8 of impurities)) of CompoundS12 and a (8S)-isomer thereof were added ethanethiol (0.12 ml, 1.6 mmol)and DBU (0.045 ml, 0.30 mmol) at -30° C., and the mixture was stirred atthe same temperature for 80 minutes.

The reaction mixture was diluted with ethyl acetate, washed with anaqueous 5% citric acid solution, an aqueous 5% sodium hydrogen carbonatesolution and an aqueous NaCl-saturated solution, and dried. The solventwas removed by distillation under reduced pressure to obtain a crudeproduct of a mixture of two isomers of Compound S13 (about 6:4, paleyellowish brown viscous material, 300 mg, crude yield 95%, purity wasabout 70%).

(e) Synthesis of p-Nitrobenzyl (5R,6S)-6-[(R)-1-Hydroxyethyl]-2-Ethylthio-1-Carbapenam-3-Carboxylate (Compound S14) ##STR38##

To a THF-water (2:1, 12 ml) solution of Compound S13 obtained in theabove item (d) was added under ice-cooling an aqueous 1N sodiumhydroxide solution (0.800 ml, 0.800 mmol) in 4 portions at every 20minutes. The mixture was stirred under ice-cooling for 30 minutes and atroom temperature for 3 hours. The THF was removed by distillation underreduced pressure and the residual aqueous solution was washed with ether(from the ether solution, Compound S13 (131 mg, 44%) was recovered).water was removed by distillation under reduced pressure to dryness.Under a dry atmosphere, para-nitrobenzyl bromide (184 mg, 0.85 mmol) wasadded to a DMF (5 ml) solution of the residue (yellowish candy-likematerial), and the mixture was stirred at room temperature for 5 hours.

In the same manner, the S13 recovered from the ether solution wassubjected to hydrolysis and para-nitrobenzyl-esterification.

Both DMF solutions were combined and the DMF was removed by distillationunder reduced pressure. The residue was diluted with ethyl acetate andwashed with an aqueous NaCl-semisaturated solution. The aqueous layerwas reverse-extracted with ethyl acetate, the ethyl acetate solutionswere combined, washed with an aqueous NaCl-saturated solution and dried,and the solvent was removed by distillation under reduced pressure. Theresidue was purified by a medium pressure silica gel columnchromatography (Lobar size B, ethyl acetate-hexane 1:1→2:1) to obtain anisomer of Compound S14 (colorless viscous material, 72 mg, 18%) and amixture (72:28, pale yellowish viscous material, 29 mg, 7.4%) of S14 andthe (8S)-isomer thereof.

Spectrum data of Compound S14;

IR (neat): 3453, 1749 cm⁻¹.

NMR: 1.24 (3H, t, J=7.5), 1.34 (3H, d, J=6.3), 1.66 (1H, br-d, J=5, OH),1.73 (1H, ddd, J=13.7, 7.7, 6.9, 1-CH), 2.52-2.70 (3H, m, 1-CH andSCH₂), 3.11 (1H, dd, J=6.8, 2.4, 6-CH), 3.80 (1H, m, 2-CH), 3.92 (1H,td, J=6.8, 2.4, 5-CH), 4.21 (1H, br, 8-CH), 4.43 (1H, d, J=5.5, 3-CH),5.28 (2H, s, PNB), 7.54 (2H, d), 8.24 (2H, d).

(f) Synthesis of p-Nitrobenzyl(5R,6S)-6-[(R)-1-Hydroxyethyl]-2-Chloro-2-Ethanesulfinyl-1-Carbapenam-3-Carboxylate(Compound S15) ##STR39##

Under a dry atmosphere, to a dichloromethane (4 ml) solution of CompoundS14 (59 mg, 0.15 mmol) were added water (0.014 ml, 0.78 mmol) andpyridine (0.036 ml, 0.45 mmol), and further added dropwise adichloromethane (2 ml) solution of iodobenzene dichloride (103 mg, 0.37mmol) under ice-cooling, and the mixture was stirred at the sametemperature for 30 minutes. Subsequently, triethylamine (0.042 ml, 0.30mmol) was added and the mixture was stirred for 10 minutes.

The reaction mixture was diluted with ethyl acetate, washed with anaqueous 5% citric acid solution and water. The aqueous layer wasreverse-extracted with ethyl acetate. The ethyl acetate solutions werecombined, washed with an aqueous NaCl-saturated solution and dried. Thesolvent was removed by distillation under reduced pressure. The residuewas purified by a medium pressure silica gel column chromatography(Lobar size A, ethyl acetate-hexane 3:2→1:0) to obtain a mixture (paleyellowish viscous material, 51 mg, 77%) of some isomers of Compound S15.

(g) Synthesis of p-Nitrobenzyl(5R,65)-6-[(R)-1-Hydroxyethyl]-2-[(3S)-1-(p-Nitrobenzyloxycarbonyl)Pyrrolidine-3-Ylthio]-1-Carba-2-Penem-3-Carboxylate(Compound S16) ##STR40##

Under an argon atmosphere, DBU (0.019 ml, 0.13 mmol) was added to a DMF(3 ml) solution of Compound S15 (51 mg, 0.11 mmol) at -30° C., and themixture was stirred for 40 minutes. Subsequently, at the sametemperature, a DMF (0.2 ml) solution of(S)-3-mercapto-1-(p-nitrobenyloxycarbonyl)pyrrolidine (41 mg, 0.15 mmol)was added and the mixture was stirred for 40 minutes.

An aqueous 5% citric acid solution was added and the mixture wasextracted with ethyl acetate. The ethyl acetate solution was washed withan aqueous NaCl-saturated solution and dried, and the solvent wasremoved by distillation under reduced pressure. The residue was purifiedby a medium pressure silica gel column chromatography (Lobar size A,ethyl acetate-hexane 2:1→1:0) to obtain Compound S16. Yellowish viscousmaterial, 44 mg. The material contained DMF (about 0.8 mg) and ethylacetate (about 4.2 mg) and it is 39 mg (55.5%) as Compound S16.

Spectrum data of Compound S16;

IR (KBr): 3429, 1777, 1705 cm⁻¹.

NMR: 1.37 (3H, d, J=6.3), 1.9-2.1 (1H, m, 4'-CH), 2.25-2.45 (1H, m,4'-CH), 3.10-3.34 (2H, m, 1-CH₂), 2.21 (1H, dd, J=6.9, 2.7, 6-CH),3.40-3.59 (2H, m), 3.60-3.78 (2H, m), 3.87 (1H, dd, J=11, 6.5),4.18-4.33 (2H, m, 5-CH and 8-CH), 5.23 (2H, s), 5.23 (1H, d, J=13.8),5.51 (1H, d, J=13.8), 7.51 (2H, d), 7.65 (2H, d), 8.22 (4H, m).

INDUSTRIAL APPLICABILITY

As clearly seen from the above, according to the present invention,6-hydroxy-6-hydroxyethylcarbapenams which are intermediates for thesynthesis of 6-hydroxy-6-hydroxyethylcarbapenem derivatives useful asmedicines can be produced more easily than by conventional methods.Also, the optically active pyrrolidine derivatives and a process forproducing the same of the present invention are useful for the synthesisof carbapenems having a hydroxyalkyl group at the 6-position.

We claim:
 1. Optically active pyrrolidine derivatives represented by thefollowing formula (XI): ##STR41## wherein R¹ represents a benzyl group,R² represents an alkyl group having 1 to 6 carbon atoms, R³ representsan alkyl group having 1 to 6 carbon atoms, a benzyl group or an allylgroup, R⁴ is selected from the group consisting of a hydrogen atom, analkyl group having 1 to 6 carbon atoms which may be substituted with aprotected hydroxyl group, a vinyl group, a phenyl group which may besubstituted, a benzyl group which may be substituted, and a heterocyclicring having 1 to 4 nitrogen or/and oxygen atoms, and R⁵ represents ahydrogen atom or a methyl group.
 2. An optically active pyrrolidinederivative according to claim 1 wherein R⁴ is a hydrogen atom and R⁵ isa methyl group.
 3. An optically active pyrrolidine derivative accordingto claim 1 wherein R⁴ and R⁵ are both a methyl group.